BRITAIN looks set to leave the European Union by summer 2019 after triggering the formal process to pull out before the end of March next year, Theresa May has said.

The 1972 European Communities Act will be swept from the statute book and end the supremacy of EU law in the UK.

The Conservative Government will also enshrine all existing EU law into British law with anything deemed unnecessary to be abolished later.

The announcement came as the Conservatives gather in Birmingham for their four-day conference. Today, the Prime Minister will lead a debate on Britain quitting the EU alongside the so-called “three Brexiteers”: Boris Johnson, the foreign secretary, Liam Fox, the international trade secretary, and David Davis, the Brexit secretary.

The announcement of the scrapping of the 1972 Act has been made with a flourish, giving it the grand title of the Great Repeal Bill, which is meant to reassure the majority of voters who backed Britain quitting the Brussels block that Brexit will mean Brexit.

Amid a deal of political shadow play, it is also designed to give certainty to businesses and protection for workers' rights that are currently part of EU law.

"This marks the first stage in the UK becoming a sovereign and independent country once again,” declared Mrs May.

"It will return power and authority to the elected institutions of our country. It means that the authority of EU law in Britain will end," she told the Sunday Times.

Mr Davis will tell the conference today: "To those who are trying to frighten British workers, saying 'when we leave, employment rights will be eroded', I say firmly and unequivocally, 'no they won't'."

The new bill is expected to be brought forward in the next parliamentary session – 2017/18 - and will not pre-empt the two-year process of leaving the EU, which begins when the Government triggers Article 50 of the Lisbon Treaty.

"It's very simple,” the Brexit secretary will say. “At the moment we leave, Britain must be back in control and that means EU law must cease to apply.

"To ensure continuity, we will take a simple approach. EU law will be transposed into domestic law, wherever practical, on exit day.

"It will be for elected politicians here to make the changes to reflect the outcome of our negotiation and our exit. That is what people voted for: power and authority residing once again with the sovereign institutions of our own country," he will add.

The repeal Bill will end the primacy of EU law, meaning rulings by the European Court of Justice will stop applying to the UK once the legislation takes effect.

It will include powers to make changes to the laws using secondary legislation as negotiations over the UK's future relationship proceed, although more wide-ranging amendments or new laws may come forward in separate Bills.

Mrs May made clear she does not want the conference to be dominated by the issue of leaving the EU and has taken the unusual step of scheduling two conference speeches, on Brexit today before delivering the traditional leader's speech to close the conference on Wednesday.

But it could prove difficult with Tory MPs divided between favouring a "hard Brexit" outside the European single market to obtain complete control over immigration, or remaining in or having close access to the free trade zone, but potentially having to comply with some EU rules.

"I'm clear that we are not going to be completely consumed by Brexit," the PM told the Sun on Sunday.

But in a sign of the debates that could dominate the fringes of the event, former education secretary Nicky Morgan will warn against interpreting the Brexit vote as "giving a licence to harsher rhetoric and returning to policies which have been rejected in the past", according to the Observer.

Meantime, Mrs May suggested seeking advice from her predecessor David Cameron was not on her list of priorities, having not spoken to him for 62 days after taking office. "It's not that I haven't been talking to him," she said. "I spent some time doing the key things that were important."

Mr Cameron's former spin doctor Sir Craig Oliver revealed that the former premier had considered in the run-up to the referendum telling voters that he wanted Britain to stay in the EU but also seek curbs on immigration.

But Mr Cameron ditched plans to seek fresh concessions in a phone call with German chancellor Angela Merkel 10 days before the referendum, Sir Craig said.

In the latest serialisation of his book, Unleashing Demons: The Inside Story Of Brexit, in the Mail on Sunday, Sir Craig said: "The idea was to test the water to see if we can agree to make plain that much more will be done on immigration.

"But as the time approaches we realise it is a fool's errand. Even supposing a magical plan can be set in train - and it certainly isn't - it will look desperate," he added.